Four-way automatic transfer switch

ABSTRACT

A system includes a first group of cassettes, each cassette including a first stationary bar, a first plurality of fixed contact members, and a first plurality of movable contact members, each of which is electrically coupled and rotatably connected to the first stationary bar and configured to contact one of the first plurality of fixed contact members. The system includes a second group of cassettes each including a second stationary bar, a second plurality of fixed contact members, and a second plurality of movable contact members, each of which is electrically coupled and rotatably connected to the second stationary bar and configured to contact one of the second plurality of fixed contact members. The system includes at least one operating mechanism to control opening and closing of the movable contact members. The first stationary bar is coupled to the second stationary bar.

FIELD

The present disclosure relates to automatic transfer switches.

BACKGROUND

An automatic transfer switch (ATS) is used to switch an electric loadback and forth between power sources (e.g., a primary power source, suchas a utility grid, and a secondary power source, such as a generator).More specifically, an automatic transfer switch allows for transferringpower from one or more sources to a load. A transfer of the load from aprimary source to a secondary source happens, for example, when theprimary source experiences a power outage or other failure. When thepower outage is over, the automatic transfer switch switches the powersource from the secondary source back to the primary source.

SUMMARY

An embodiment of the disclosure relates to a system. The system includesa first group of one or more cassettes. Each cassette of the first groupof cassettes includes a first stationary bar, a first plurality of fixedcontact members, and a first plurality of movable contact members. Eachof the first plurality of movable contact members is electricallycoupled and rotatably connected to the first stationary bar andconfigured to contact one of the first plurality of fixed contactmembers. The system further includes a second group of one or morecassettes. Each cassette of the second group of cassettes includes asecond stationary bar, a second plurality of fixed contact members, anda second plurality of movable contact members. Each of the secondplurality of movable contact members is electrically coupled androtatably connected to the second stationary bar and configured tocontact one of the second plurality of fixed contact members. The systemadditionally includes at least one operating mechanism configured tocontrol opening and closing of the first plurality of movable contactmembers and the second plurality of movable contact members, and foreach cassette of the first group of cassettes, a coupling configured tocouple the first stationary bar of the cassette of the first group ofcassettes to the second stationary bar of a cassette of the second groupof cassettes.

Another embodiment relates to a method. The method includes coupling afirst group of cassettes to a second group of cassettes. Each cassetteof the first group of cassettes and the second group of cassettesincludes a source bar structured to connect to a corresponding powersource, and at least one movable bar electrically coupled and rotatablyconnected to a stationary bar. The method includes directing current toflow through the stationary bar and at least one movable bar of eachcassette of the first group of cassettes or the second group ofcassettes so as to induce an electromagnetic force, and causing theelectromagnetic force to act on at least one movable bar of eachcassette of the first group of cassettes or the second group ofcassettes so as to move at least one movable bar toward the source barof each cassette of the first group of cassettes or the second group ofcassettes. The coupling includes connecting a stationary bar of thefirst group of cassettes to a stationary bar of the second group ofcassettes.

Yet another embodiment relates to a system comprising an automatictransfer switch. The automatic transfer switch includes a stationary barhaving a first end and a second end parallel to the first end; a firstsource bar and a second source bar disposed on a first side of thestationary bar; a third source bar and a fourth source bar disposed on asecond side of the stationary bar that is opposed to the first side; afirst movable bar electrically coupled and rotatably connected to thestationary bar at the first side and configured to contact the firstsource bar; and a second movable bar electrically coupled and rotatablyconnected to the stationary bar at the first side and configured tocontact the second source bar. The switch further includes a thirdmovable bar electrically coupled and rotatably connected to thestationary bar at the second side and configured to contact the thirdsource bar, and a fourth movable bar electrically coupled and rotatablyconnected to the stationary bar at the second side and configured tocontact the fourth source bar.

An additional embodiment relates to a system including an automatictransfer switch cassette. The automatic transfer switch cassetteincludes a stationary bar and four source bars, each of the four sourcebars disposed on a same side of the stationary bar. The automatictransfer switch cassette further includes four movable bars. Each of thefour movable bars is electrically coupled and rotatably connected to thestationary bar and configured to contact one of the four source bars.

These and other features, together with the organization and manner ofoperation thereof, will become apparent from the following detaileddescription when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an automatic transfer switch cassette.

FIG. 2A is a schematic diagram of forces on a movable bar of theautomatic transfer switch of FIG. 1 at a closed position.

FIG. 2B is a schematic diagram illustrating current flowing throughcontacts of the automatic transfer switch of FIG. 1 at a closedposition.

FIG. 3 is a schematic diagram of a four-way automatic transfer switchaccording to some embodiments.

FIG. 4 is a schematic diagram of a configuration in which four sourcesmay be connected to one load, according to some embodiments.

FIG. 5 is a schematic diagram of a controller according to someembodiments.

FIG. 6 is a process diagram depicting a method according to someembodiments.

FIG. 7 is a schematic diagram showing multiple sources connected to aload, according to some embodiments.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe figures, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated and made part of this disclosure.

In some situations, automatic transfer switches are coupled together toserve various purposes. For example, automatic transfer switches areoften coupled in a “bypass” configuration for critical powerinstallations. In the bypass configuration, two or more automatictransfer switches are coupled in parallel and driven by a commoncontroller. If one automatic transfer switch fails or needs maintenance,it can be automatically bypassed by the other automatic transferswitches or manually bypassed.

When multiple automatic transfer switches are coupled together, thespace needed to accommodate the automatic transfer switches may increasesubstantially. For example, each automatic transfer switch may beprovided in its own enclosure rather than a common enclosure, increasingthe overall footprint (space needed to accommodate the system).Additionally, when multiple automatic transfer switches are coupledtogether, a large extent of electrical conduits runs may be needed forconnecting the automatic transfer switches in their respectiveenclosures. In particular, electrical conduits are needed when ‘daisychaining’ multiple automatic transfer switches together.

Further still, the individual automatic transfer switches cannot bereadily connected in parallel. In addition to each automatic transferswitch having its own enclosure, as mentioned above, each automatictransfer switch may also have its own actuator and controller, which,together with the multiple separate enclosures, collectively enlarge theoverall footprint, make coordination of the switches complex, andincrease the cost and amount of equipment needed.

Automatic transfer switches generally switch an electrical load betweentwo power sources. A typical configuration is a local load that is beingswitched between a utility grid that is used as a power source and abackup generator, such as during a power failure. If more than twosources are available to be switched between or coupled in parallel,each additional source requires another ATS switch and associatedcontrol to allow it to be utilized and switched in to power the load. Inparticular, typical approaches require using two automatic transferswitches to route power from one of three sources to a load, each ofwhich has a separate dedicated controller. Generalized, for N sources,it is common to need to utilize N-1 ATS switches, requiring the ATSswitches to be configured in either a pyramid or daisy chainconfiguration to couple or switch between the N sources.

When the ATS switches are configured in pyramid configuration, the loadoutput of each individual ATS switch is coupled to a source input of anATS switch in the layer above it and each of its source inputs arecoupled to the load outputs of two other ATS switches in the layerbelow. The first layer of ATS switches are coupled to the N sources, andthe load is coupled at a final ATS switch at the load output connectionat the top of the configuration. Alternatively, in a daisy chainconfiguration, one source input of each ATS switch of the daisy chain iscoupled to one of the N sources, with the load output coupled to aninput for the next ATS switch above it in the chain, and the remainingsource input coupled to the load output of the next ATS below it in thechain. The first ATS switch in the chain has two sources coupled to itssource inputs and the load output of the final ATS switch in the chainis coupled to the load.

For at least these reasons, it is desirable to provide an automatictransfer switch allowing for efficiently coupling to and transferringelectrical power from multiple sources (e.g., four sources) to a load,either singly or coupling two or more sources in parallel, within acommon enclosure. In particular, it is advantageous to provide a systemwith one enclosure, within which a switch allows for switching fromthree or four or more sources to a load.

Exemplary embodiments disclosed herein allow for connecting three orfour sources to one load, within a single enclosure, and may employ asingle dedicated automatic transfer switch controller. Furthermore, suchembodiments may also allow for paralleling of any of two or moreelectrical sources (e.g., a utility, a solar power source, an energystorage device, a wind power source, and/or any other source ofelectrical power either directly or via an energy conversion device suchas an inverter).

In at least one embodiment, a system includes multiple groups ofcassettes. Each group of cassettes has one or more cassettes in it. Eachcassette or cassette group has two source inputs (first and secondsource poles) and a central stationary load contact bar. Two movablecontact members then connect between the source input poles and thestationary load contact bar. The two groups of cassettes with two sourceinputs each then have their stationary load contact bars jumperedtogether to form a single common output, while upper and lower rotatingactuation cross bars are also split left/right to drive the upper andlower movable contact arms in each group of cassettes. Each input/outputgroup of cassettes can also have multiple sub-groups in them, eachhandling a different phase of the connection (one, two, three, or more,with or without the neutral).

Further, in at least one embodiment, a system includes a first group ofone or more cassettes, or a single cassette and an accompanied solidbusbar, and a second group of at least one or more cassettes, or asingle cassette and an accompanied solid busbar. The first group ofcassettes includes a first plurality of movable contact members, a firstplurality of fixed contact member, and a first stationary bar. Thesecond group of cassettes includes a second plurality of movable contactmembers, a second plurality of fixed contact members, and a secondstationary bar. The system further includes a first operating mechanismand a second operating mechanism to control opening and closing of theplurality of movable contact members; and a coupling configured tocouple an output of the first group of cassettes to an output of thesecond group of cassettes.

Referring to FIG. 1, a schematic diagram of an automatic transfer switch(ATS) cassette 100 is shown. The ATS shown in FIG. 1 is described inmore detail in US Patent App. Publication No. 2017/0117104, entitled“Low Profile Blow-On Force Automatic Switch,” published Apr. 27, 2017,the entirety of which is hereby incorporated by reference for thetechnical disclosures and background therein.

ATS cassette 100 includes a first source bar 102 with a first sourcecontact pad 103, a second source bar 104 with a second source contactpad 105, a stationary bar 106, a first movable bar 108 with a firstmovable contact pad 109, a second movable bar 110 with a second movablecontact pad 111, a first spring and mechanical linkage 114, and a secondspring and mechanical linkage 116. As seen in FIG. 1, the movablecontact bars 108, 110 are provided at a first location and a secondlocation, respectively. In some embodiments, the first source bar 102and the second source bar 104 are fixed on the cassette 100. The firstsource bar 102 may be connected to a primary power source (notillustrated in the present figure), for example, a utility grid.

The second source bar 104 may be coupled to a secondary power source(not illustrated in the present figure), for example, a generator set(also referred to as a “genset”). In some embodiments, the secondarypower source may be any other electrical power source.

In some embodiments, the stationary bar 106 is also fixed on thecassette 100. The stationary bar 106 may be coupled to an electricalload (not illustrated in the present figure), for example, a resistiveload and/or a motor load. The load to which bar 106 may be connected mayinclude, but is not limited to, appliances, lights, or other loadsdesirable to power in the event of a utility grid failure. In someembodiments, stationary bar 106 is a T-shaped bar, also referred to as aT-joint.

The first movable bar 108 and the second movable bar 110 are eachelectrically coupled and rotatably connected to the stationary bar 106.The first and second movable bars 108 and 110 each rotate between aclosed position and an open position. As used herein, the “closedposition” refers to the situation in which the movable bar engages thecorresponding source bar of the power source that supplies power. The“open position” refers to the situation in which the movable bardisengages the corresponding source bar of the power source that isdisconnected from the load. When power is being supplied from theprimary power source, the first movable contact pad 109 at an end of thefirst movable bar 108 engages the first source contact pad 103 at an endof the first source contact 102.

The first movable bar 108 is in the closed position and the electricalload is electrically connected to the primary power source. When thereis an interruption in the primary power source, the first movable bar108 rotates from the closed position to the open position to disengagethe first movable contact pad 109 from the first source contact pad 103.The second movable bar 110 rotates from the open position to the closedposition to allow the second movable contact pad 111 at an end of thesecond movable bar 110 to engage the second source contact pad 105 at anend of the second source contact 104. The electrical load iselectrically connected to the secondary power source. A similaroperation is performed to transfer back to the primary power source fromthe secondary power source when the interruption is over. In someembodiments, the contacts pads 103, 105, 109, and 111 are made of one ormore metals or metal alloys, such as a silver or copper alloy. It isnoted that the load can be transferred using an “open transition” (wherethe first source is disconnected before the second is coupled, leavingthe load briefly unpowered—“break before make”) or a “closed transition”(where both sides of the switch are briefly closed at the same time andthe sources are paralleled together to make the power transitionseamless, but requiring synchronization of the sources—“make beforebreak”) using the ATS switch. It is further noted that the ATS can alsoparallel the two sources to the load by leaving both sides coupled orelectrically isolate the load from the sources by opening both sides ofthe switch.

Some automatic transfer switches use an electromagnetic force (EMF)induced by an electrical current flowing through the switch to assistkeeping together contacts that connect an electrical load to the powersources. For example, a “blow-on force” is the EMF force generated thatbiases the switch contacts towards one another and presses them togetherwhen current is flowing. The current in the switch needs to follow aproper path to generate and maintain the blow-on force.

Referring to FIG. 2A, schematic diagram of blow-on and blow-off forceson a movable bar of the automatic transfer switch of FIG. 1 is shown ina closed position. The current flow path is A-A′ in the stationary bar106, B-B′ in the first movable bar 108, and C-C′ in the first sourcecontact 102. Since the current flow directions are opposite in thestationary bar 106 and the first movable bar 108, a repulsiveelectromagnetic force is induced that pushes the first movable bar 108away from the stationary bar 106. This is the blow-on force that biasesthe first movable contact pad 109 towards the first source contact pad103 and assists the closing force provided by the first spring andmechanical linkage 114.

FIG. 2B illustrates current flowing through the first movable contactpad 109 and the first source contact pad 103. As shown, the in and outcurrents between the first movable contact pad 109 and the first sourcecontact pad 103 are not on the same axis but form an angle. As a result,the in current and the out current induce a repulsive electromagneticforce between the first movable contact pad 109 and the first sourcecontact pad 103 which pushes the first movable contact pad 109 away fromthe first source contact pad 103. This is a blow-off force thatseparates the contacts apart.

Referring back to FIG. 1, the cassette 100 may further include springsto help maintain a contact force during operation. As shown in thefigure, the first spring and mechanical linkage 114 includes a spring114 a that pulls from the bottom of the first movable bar 108 and aspring 114 b that presses on top of the first movable bar 108. Thesecond spring and mechanical linkage 116 includes a spring 116 a thatpulls from the bottom of the second movable bar 110 and a spring 116 bthat presses on top of the second movable bar 110. It is noted that insome embodiments, springs 114 a and 114 b can be combined into a singlespring 114, and so can springs 116 a and 116 b. In some embodiments, thefirst spring and mechanical linkage 114 and the second spring andmechanical linkage 116 each apply a contact force on the correspondingmovable bar at the closed position.

FIG. 3 depicts a four-way automatic transfer switch utilizing jumperedconnection and divided cassette groups and operating crossbars toprovide four-way functionality according to some embodiments. As shownin FIG. 3, a four-way automatic transfer switch (ATS) 200 includes twogroups of four of the cassettes 100. In particular, the four-way ATS 200includes a first group 201 of four cassettes 100 and a second group 202of four additional cassettes 100. Each of the cassettes 100 in the firstand second groups 201, 202 may be positioned to route electrical powerfrom an input thereof to an output thereof. Although FIG. 3 depicts thegroups 201, 202 each including four cassettes, in some embodiments, eachof the groups 201, 202 includes at least two cassettes. The groups arenot limited to four cassettes. Further, in some embodiments, the groups201, 202 may have a differing number of cassettes in accordance with acurrent carrying requirement. It is noted that other embodiments mayhave differing numbers or sizes of cassettes to enable differing numberof phases, differing current carrying capacity, or differentapplications. It is also noted that in other embodiments, the number ofcassettes can be different from side to side or cassette group.

In some embodiments, the ATS 200 may be configured as a one, two, orthree-phase ATS, or may have still further phases, and the inputs mayinclude any electrical power source such as utility, a solar powersource, generator, an energy storage device, and a wind power source.The ATS 200 of FIG. 3 details a three-phase configuration of anembodiment with four source inputs, with each source input switchingthree phases and a neutral. It is noted that in the ATS 200, each groupof four cassettes provides inputs for two three phase sources (threephases and a neutral) and the load outputs of the cassettes are jumperedwith bus bar connections (203A-203D) together to provide a single threephase and a neutral output connection.

For example, the inputs may include (1) a first phase SP1 of a solarinverter, a second phase SP2 of a solar inverter, a third phase SP3 of asolar inverter, and a solar inverter neutral SN; (2) a first phase WP1of a wind power source, a second phase WP2 of a wind power source, athird phase WP3 of a wind power source, and a wind power neutral WN; (3)a first phase GP1 of a generator set, a second phase GP2 of a generatorset, a third phase GP3 of a generator set, and a generator set neutralGN; and (4) a first phase UP1 of a utility, a second phase UP2 of autility, a third phase UP3 of a utility, and a utility neutral UN.Although a three-phase configuration is shown in FIG. 3, in someembodiments, the ATS 200 may be provided with a single phaseconfiguration or a two-phase configuration. It is noted that other powersources and phase configurations are possible. For example, a singlephase configuration may include either two switched poles per cassettegroup or a single switched pole per cassette group with an accompaniedsolid busbar for a ground or neutral connection.

Further, in at least one embodiment, the first group 201 of cassettes100 may include the first through third generator set phases and thegenerator set neutral at the first source bar 102, and the first throughthird wind phases and the wind neutral at the second source bar 104. Thesecond group 202 of cassettes 100 may include the first through thirdutility phases and the utility neutral at the first source bar 102 andthe first through third solar inverter phases and the solar inverterneutral at the second source bar 104.

The ATS 200 may further include one or more actuators (operatingmechanisms). In at least one embodiment, ATS 200 includes a plurality ofactuators, which may be electromagnetic solenoids, for example. Theactuators serve to drive the rotation of crossbars which are locatedthrough the perpendicular of the cassettes and in turn drive therotation of cassette cams which rotate the cassette moveable bar.Traditionally, two crossbars are required, one across the top and bottomof the ATS cassettes, respectively, to drive the independent rotation ofeach of the two cassette movables. Multiple cassettes may be driven offof the same set of crossbars to coordinate the rotation of moveablesacross cassette groups. Multiple cassettes may be coupled together inparallel by phases within the ATS to carry sufficient current for theselected application.

In some embodiments, a first actuator (a first operating mechanism) isprovided at an end of the first group 201 of cassettes 100, and a secondactuator (a second operating mechanism) is provided at an end of thesecond group 202 of cassettes 100. The first actuator is configured todrive the first group 201 of cassettes, and the second actuator isconfigured to drive the second group 202 of cassettes. In someembodiments, a shaft connected to the first actuator and a shaftconnected to the second actuator may be enlarged so as to accommodatedriving of the cassette groups 201, 202, respectively.

In some embodiments, power may be routed from either set of inputs(i.e., the inputs from the generator set phases and the wind powerphases, and the inputs from the utility phases and the solar inverterphases) of the groups 201, 202 of cassettes 100, respectively, to theoutputs of the cassettes 100. Further, in some embodiments, connectors203 may be employed to tie bus bars of the outputs together. Theconnectors 203 may be shorting bars or jumpers, for example.

Where shorting bars are provided as the connectors 203, they may serveto mitigate thermal effects due to eddy currents and the inherentresistance of the current carrying components such as busbars and cablesby spreading the current flow of each of the phases across multipleconductors and cassettes. It is noted that in some embodiments, cablesare generally flexible conductors having a conducting core that can be asolid conductor, multiple twisted strands, braided strands, or otherflexible conductor form, whereas jumpers or shorting bars are generallyrigid conductors having solid form for coupling between electricalconnections or bus bars. In some embodiments, the shorting bars may beoutfitted with a heat sink, such as a cooling fin 209, that may bemolded onto the bars so as to absorb and dissipate heat from other partsof the ATS 200, e.g., from the stationary bar 106. The fin 209 may bemade of highly conductive material so as to increase the amount of heatbeing conducted away from the ATS 200 through the fin.

By using the connectors 203 to tie the output bus bars together, aninput power may be selected from any one of four sources to route to oneset of electrical outputs. Further, the above-described configurationallows for any two sources to be paralleled, so that any of the sourcescan be paralleled with a smart grid, for example. Furthermore, in someembodiments, the configuration shown in FIG. 3 may be scaled so as toprovide power from five, six, seven or eight sources to one load, forexample.

In at least one embodiment, connectors 203 include four connectors.Specifically, a first connector 203A may connect a first output phase ofthe first group 201 of cassettes 100 to a first output phase of thesecond group 202 of cassettes 100. A second connector 203B may connect asecond output phase of the first group 201 of cassettes to a secondoutput phase of the second group 202 of cassettes. A third connector203C may connect a third output phase of the first group 201 ofcassettes to a third output phase of the second group 202 of cassettes.Finally, a fourth connector 203D may connect an output neutral of thefirst group 201 of cassettes to an output neutral of the second group202 of cassettes.

In some embodiments, the ATS 200 may be controlled by a control systemor a programmable logic controller (PLC). Referring to FIG. 5, aschematic diagram of a control system is shown according to an exemplaryembodiment. The ATS 200 may be coupled to the multiple sources andconfigured to switch a load therebetween, as discussed above. The ATS200 includes a controller 223 and a communication interface 225, amongother components. The controller 223 is configured to control theoperations of the ATS 200 and facilitate load transfer among sources.The controller 223 may be implemented in various forms of hardware,firmware, special purpose processors, or a combination thereof. In someembodiments, the controller 223 is implemented on a computer platformhaving a processor 227 and a memory 229.

The processor 227 may be structured to selectively execute instructions,commands, and the like stored by the memory 229. The processor 227 maybe implemented as a general-purpose processor, an application specificintegrated circuit (ASIC), one or more field programmable gate arrays(FPGAs), a digital signal processor (DSP), a group of processingcomponents like mentioned above, or any other suitable electronicprocessing components. The memory 229 (e.g., NVRAM, RAM, ROM, FlashMemory, hard disk storage, etc.) may store data and/or computer code forfacilitating the various processes described herein. Accordingly, thememory 229 may be or include tangible, non-transient volatile memory ornon-volatile memory.

The controller 223 may receive and transmit information from and toother devices via the communication interface 225 over a network. Thecommunication interface 225 may include any communication interfaceappropriate or compatible with the network, such as a modem, a networkinterface card (NIC), a CAN bus, a mode bus, an Ethernet, a serial bus,a wireless transceiver, etc. In at least one embodiment, the controller223 is programmed to control movement of the movable bars of thecassettes 100 of each of the cassette groups 201, 202 in the ATS 200shown in FIG. 3, for example.

Furthermore, in at least one embodiment, the controller 223 may receiveinformation relating to an operational state of one or more of aplurality of power sources (e.g., the utility, the genset, the windpower source, the energy storage device, or the solar inverter source).For example, the controller 223 may receive, via the network interface225, information indicating that one or more of the sources is in afailed state or an operational state. The controller 223 may, inresponse to information from the network indicating that a power sourceis in a failed state, control the ATS 200 so as to switch to anon-failed (operational) power source. Similarly, the controller 223 mayreceive information indicating that one of the first group 201 ofcassettes and the second group 202 of cassettes maintains powertransmission upon failure of the other of the first group 201 ofcassettes and the second group 202 of cassettes.

Referring now to FIG. 4, an exemplary ATS cassette configuration isshown in which four sources may be connected to one load with a front toback coupling of ATS cassettes to gain an increased number of sourceinputs, according to some embodiments. FIG. 4 shows a differentconfiguration from FIG. 3. FIG. 3 depicts a four-way automatic transferswitch utilizing a jumpered stationary bar connection (e.g., viaconnector 203) or load output connection and divided cassette groups201, 202, and operating crossbars to provide four-way functionality in asingle layer of ATS cassettes. In contrast, FIG. 4 depicts two or morelayers of ATS cassettes that have a common stationary bar or coupledstationary bars between the differing layers of ATS cassettes to provideadditional source inputs with a single load output connection for theATS switch. The configuration of FIG. 4 includes a stationary bar (e.g.,a stationary bar shaped as a T-joint) 106 to which four sources 102,104, 112, 118 are coupled. Each of the four sources may be coupled to arespective movable contact member in the manner described above inregard to FIG. 1.

Whereas the cassettes and cassette groups are located side-by-side inFIG. 3, the cassettes in FIG. 4 are located front-to-back, increasingthe depth requirements of the electric cabinet containing the ATSswitch, but allowing for a shorter connection distance on the load busor stationary bar 106 and facilitating multiple source ATS operation.The ATS of FIG. 4 can also be used in a critical power redundant bypassconfiguration if source 1 102 and source 2 104 are coupled in parallelto a first power source, and source 3 112 and source 4 118 are coupledin parallel to a second power source. In at least one embodiment, theconnection between the front and back cassettes in FIG. 4 is such thatthe cassettes can be disconnected, then one set at a time can be removedfor test or service. While FIGS. 1-4 depict blow-on style ATS switches,non-blow-on ATS switches and cassette-based embodiments may beimplemented. It is further noted that the four way side-by-side dividedand jumpered cassette group ATS embodiment depicted in FIG. 3 can becombined with the four way front-to-back stationary bar and loadconnection embodiment of FIG. 4 to further increase the number ofavailable source connections or to add bypass redundancy for criticalpower applications.

Furthermore, the T-joint 106 may be made longer so as to accommodatesources 1-4 (e.g., the utility, the genset, the wind power source,energy storage device, and the solar inverter source). The ATS may beconnected in a wired or wireless manner to controller 223 discussedabove. In some embodiments, in the above-described configuration, eachof the first movable bar, the second movable bar, the third movable barand the fourth movable bar associated with the respective sources 102,104, 112 and 118 is movable by the associated rotating crossbars andmechanical linkage 114, 116 of the switch. In addition, in the blow-onATS switch shown in FIG. 4, a blow-on electromagnetic force is presentduring operation so as to bias the respective first movable bar, secondmovable bar, third movable bar and fourth movable bar towards the firstsource bar, the second source bar, the third source bar and the fourthsource bar, respectively, and the electromagnetic force is induced bycurrent flowing through the stationary bar and the respective one of thefirst movable bar, the second movable bar, the third movable bar and thefourth movable bar.

Referring now to FIG. 6, a process diagram depicting a method 600according to at least one exemplary embodiment is shown. The methodincludes coupling a first group of cassettes to a second group ofcassettes (step 601), such as the first group 201 of cassettes and thesecond group 202 of cassettes described above in regard to FIG. 3. Eachcassette of the first group 201 of cassettes and the second group 202 ofcassettes includes a source bar structured to connect to a correspondingpower source, and at least one movable bar electrically coupled androtatably connected to a stationary bar, as shown in FIG. 3.

The method 600 further includes directing current to flow through thestationary bar and at least one movable bar of each cassette of thefirst group of cassettes or the second group of cassettes so as toinduce an electromagnetic force (step 602), and causing theelectromagnetic force to act on at least one movable bar of eachcassette of the first group of cassettes or the second group ofcassettes so as to move at least one movable bar toward the source barof each cassette of the first group of cassettes or the second group ofcassettes (603). As described above, the coupling includes connecting astationary bar of the first group of cassettes to a stationary bar ofthe second group of cassettes. The coupling may be accomplished using ashorting bar or jumper for an electrical connection. Accordingly, suchmethods allow for the interconnecting of both blow-on and non-blow onATS switches with side-by-side division using jumpers and dividedrotating crossbars, or front/back division or placement so as to readilyincrease (e.g., multiply) the number of source connections for an ATS tocouple a load to N possible sources.

Another configuration is shown in FIG. 7 and uses a low-profilehalf-cassette design as in U.S. patent application publication US2017/0117104 A1, but is connected either front-to-back or back-to-frontto allow the connection of multiple sources. This scheme has the addedadvantage of always generating blow-on force regardless of the directionof current. The half-cassette locations are not limited to a horizontalorientation as a group or as individual cassettes, but can also bestacked vertically with a common load bus, with the load bus changingsize as the cassette location requires. If the connections between thehalf cassettes are such that they can be disconnected, thisconfiguration can also facilitate a bypass configuration where one ormore half cassettes can be disconnected and removed for test or service.It is noted that the jumpered connection, side-by-side divided cassettegroups and operating crossbars detailed in FIG. 3 can also be utilizedin the low profile half-cassette embodiment of FIG. 7 to provideadditional source inputs and functionality. In particular, at least oneembodiment may include an automatic transfer switch cassette includingfour source bars being disposed on a same side as a stationary bar, andfour movable bars electrically coupled and rotatably connected to thestationary bar and configured to contact one of the four source bars.

While this specification contains specific implementation details, theseshould not be construed as limitations on the scope of any inventions orof what may be claimed, but rather as descriptions of features specificto particular implementations. Certain features described in thisspecification in the context of separate implementations can also beimplemented in combination in a single implementation. Conversely,various features described in the context of a single implementation canalso be implemented in multiple implementations separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or variation of a subcombination.

Similarly, while operations may be depicted in a particular order, thisshould not be understood as requiring that such operations be performedin the particular order shown or in sequential order, or that alloperations be performed, to achieve desirable results. Moreover, theseparation of various aspects of the implementations described aboveshould not be understood as requiring such separation in allimplementations, and it should be understood that the described methodscan generally be integrated in a single application or integrated acrossmultiple applications.

The construction and arrangements of the ATS systems as shown in thevarious exemplary embodiments, are illustrative only. Although onlycertain embodiments have been described in detail in this disclosure,many modifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, orientations, etc.)without materially departing from the novel teachings and advantages ofthe subject matter described herein. Some elements shown as integrallyformed may be constructed of multiple parts or elements, the position ofelements may be reversed or otherwise varied, and the nature or numberof discrete elements or positions may be altered or varied. The order orsequence of any process, logical algorithm, or method steps may bevaried or re-sequenced according to alternative embodiments. Othersubstitutions, modifications, changes and omissions may also be made inthe design, operating conditions and arrangement of the variousexemplary embodiments without departing from the scope of the presentinvention.

As may be utilized herein, the term “about” and similar terms areintended to have a broad meaning in harmony with the common and acceptedusage by those of ordinary skill in the art to which the subject matterof this disclosure pertains. It should be understood by those of skillin the art who review this disclosure that these terms are intended toallow a description of certain features described and claimed withoutrestricting the scope of these features to the precise numerical rangesprovided. Accordingly, these terms should be interpreted as indicatingthat insubstantial or inconsequential modifications or alterations ofthe subject matter described and claimed are considered to be within thescope of the invention as recited in the appended claims.

The terms “coupled,” “connected,” and the like as used herein mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent) or moveable (e.g., removableor releasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below,” etc.) are merely used to describe the orientation ofvarious elements in the drawings. It should be noted that theorientation of various elements may differ according to other exemplaryembodiments, and that such variations are intended to be encompassed bythe present disclosure.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for thesake of clarity.

What is claimed is:
 1. A system, comprising: a first group of one ormore cassettes, each cassette of the first group of cassettescomprising: a first stationary bar; a first plurality of fixed contactmembers; and a first plurality of movable contact members, each of thefirst plurality of movable contact members electrically coupled androtatably connected to the first stationary bar and configured tocontact one of the first plurality of fixed contact members; a secondgroup of one or more cassettes, each cassette of the second group ofcassettes comprising: a second stationary bar; a second plurality offixed contact members; and a second plurality of movable contactmembers, each of the second plurality of movable contact memberselectrically coupled and rotatably connected to the second stationarybar and configured to contact one of the second plurality of fixedcontact members; at least one operating mechanism configured to controlopening and closing of the first plurality of movable contact membersand the second plurality of movable contact members; and for eachcassette of the first group of cassettes, a coupling configured tocouple the first stationary bar of the cassette of the first group ofcassettes to the second stationary bar of a cassette of the second groupof cassettes, wherein the first stationary bar of a first cassette ofthe first group of one or more cassettes is coupled to the secondstationary bar of a first cassette of the second group of one or morecassettes, and the first stationary bar of a second cassette of thefirst group of one or more cassettes is coupled to the second stationarybar of a second cassette of the second group of one or more cassettes.2. The system of claim 1, wherein at least one of the first group of oneor more cassettes or the second group of one or more cassettes isstructured to connect to a utility grid.
 3. The system of claim 1,wherein one of the first group of one or more cassettes and the secondgroup of one or more cassettes maintains power transmission upon failureof the other of the first group of one or more cassettes and the secondgroup of one or more cassettes.
 4. The system of claim 1, wherein eachof the first fixed contact member and the second fixed contact member isconfigured to connect to a different power source.
 5. The system ofclaim 1, wherein the first group of one or more cassettes comprises fourcassettes and the second group of one or more cassettes comprises fourcassettes.
 6. The system of claim 1, wherein the at least one operatingmechanism comprises a first actuator configured to drive the first groupof one or more cassettes and a second actuator configured to drive thesecond group of one or more cassettes, and the output of the first groupof one or more cassettes is coupled to the output of the second group ofone or more cassettes via a shorting bar.
 7. The system of claim 1,wherein the first group of one or more cassettes and the second group ofone or more cassettes are arranged in an automatic transfer switchhaving a single-phase configuration, a dual-phase configuration, or athree-phase configuration.
 8. The system of claim 1, wherein thecassettes are low-profile half-cassettes.
 9. The system of claim 1,wherein the first group of one or more cassettes includes a differentnumber of cassettes from the second group of one or more cassettes inaccordance with a current carrying requirement.
 10. A method,comprising: coupling a first group of cassettes to a second group ofcassettes, wherein each cassette of the first group of cassettes and thesecond group of cassettes includes at least one source bar structured toconnect to a corresponding power source, and at least one movable barelectrically coupled and rotatably connected to a stationary bar,directing current to flow through the stationary bar and the at leastone movable bar of each cassette of the first group of cassettes or thesecond group of cassettes so as to induce an electromagnetic force, andcausing the electromagnetic force to act on the at least one movable barof each cassette of the first group of cassettes or the second group ofcassettes so as to move the at least one movable bar toward the at leastone source bar of each cassette of the first group of cassettes or thesecond group of cassettes, the coupling comprising connecting a firststationary bar of a first cassette of the first group of cassettes to asecond stationary bar of a first cassette of the second group ofcassettes, and connecting a first stationary bar of a second cassette ofthe first group of cassettes to a second stationary bar of a secondcassette of the second group of cassettes.
 11. The method of claim 10,further comprising connecting the first stationary bar of the firstcassette of the first group of cassettes and the second stationary barof the first cassette of the second group of cassettes with a firstjumper.
 12. The method of claim 10, further comprising connecting thefirst stationary bar of the first cassette of the first group ofcassettes and the second stationary bar of the first cassette of thesecond group of cassettes with a shorting bar.
 13. The method of claim12, further comprising molding a cooling fin on the shorting bar. 14.The method of claim 12, wherein at least one of the stationary bar of acassette in the first group of cassettes or the stationary bar of acassette in the second group of cassettes comprises a T-shaped bar. 15.The method of claim 12, wherein: each of the first group of cassettesand the second group of cassettes comprises four cassettes; and thecoupling further comprises connecting (1) a stationary bar of a thirdcassette of the first group of cassettes to a stationary bar of a thirdcassette of the second group of cassettes, or (2) a stationary bar of afourth cassette of the first group of cassettes to a stationary bar of afourth cassette of the second group of cassettes.
 16. The method ofclaim 12, further comprising: driving the first group of cassettes via afirst actuator; and driving the second group of cassettes via a secondactuator.
 17. The method of claim 12, further comprising: connecting oneof the first group of cassettes and the second group of cassettes to afirst source of a plurality of electrical energy sources; and connectingthe other of the first group of cassettes and the second group ofcassettes to a second source of the plurality of electrical energysources.
 18. The method of claim 12, wherein: each cassette of the firstgroup of cassettes includes a first movable bar, a second movable bar, afirst source bar, and a second source bar, each cassette of the secondgroup of cassettes includes a first movable bar, a second movable bar, afirst source bar, and a second source bar, and an output of the firstgroup of cassettes and an output of the second group of cassettes arejumpered together.
 19. The method of claim 12, wherein the first sourceand the second source are coupled in parallel to another source.
 20. Themethod of claim 15, further comprising connecting the first stationarybar of the first cassette of the first group of cassettes to the secondstationary bar of the first cassette of the second group of cassettes bya first connector to connect a first output phase of the first group ofcassettes to a first output phase of the second group of cassettes,wherein the first stationary bar of the second cassette of the firstgroup of cassettes is connected to the second stationary bar of thesecond cassette of the second group of cassettes by a second connectorto connect a second output phase of the first group of cassettes to asecond output phase of the second group of cassettes; the stationary barof the third cassette of the first group of cassettes is connected to astationary bar of the third cassette of the second group of cassettes bya third connector to connect a third output phase of the first group ofcassettes to a third output phase of the second group of cassettes; andthe stationary bar of the fourth cassette of the first group ofcassettes is connected to the stationary bar of the fourth cassette ofthe second group of cassettes by a fourth connector to connect an outputneutral of the first group of cassettes to an output neutral of thesecond group of cassettes.